# PostgreSQL

> Wiki for PostgreSQL 18: SQL & querying (joins/CTEs/windows), DDL/DML, data types incl. JSON/JSONB, indexes, transactions & MVCC, performance/EXPLAIN, PL/pgSQL, psql, roles & security, and operations.
> Covers: PostgreSQL 18 for practitioners: SQL and querying (joins, subqueries, CTEs, window functions), DDL (tables/schemas/constraints/partitioning), DML (incl. ON CONFLICT upsert, RETURNING), data types including JSON/JSONB, indexes (all types, partial/expression), transactions and MVCC (isolation levels, locking), performance tuning with EXPLAIN, PL/pgSQL, the psql client, roles/privileges/RLS, backups (pg_dump), and a reference catalog.
> Not covered: The exhaustive SQL-command and function reference, partitioning/full-text-search deep dives, the extension ecosystem internals, replication/HA configuration, and server administration beyond basics — use postgresql.org/docs. Pinned to PostgreSQL 18; freshness = source fetch date below.
> Current as of: 2026-06-25 (18)

- [LLM Wiki](/raw/postgresql/README.md)
- [PostgreSQL KB — Master Index](/raw/postgresql/wiki/index.md)
- [Constraints](/raw/postgresql/wiki/concepts/constraints.md)
- [Data Types](/raw/postgresql/wiki/concepts/data-types.md)
- [Data Manipulation: INSERT, UPDATE, DELETE](/raw/postgresql/wiki/concepts/dml.md)
- [Indexes and Index Types](/raw/postgresql/wiki/concepts/indexes.md)
- [JSON and JSONB](/raw/postgresql/wiki/concepts/json.md)
- [PL/pgSQL — SQL Procedural Language](/raw/postgresql/wiki/concepts/plpgsql.md)
- [Queries, Table Expressions, and CTEs](/raw/postgresql/wiki/concepts/queries-and-joins.md)
- [Roles, Privileges, and Row-Level Security](/raw/postgresql/wiki/concepts/roles-and-security.md)
- [Schemas and Tables](/raw/postgresql/wiki/concepts/schema-and-tables.md)
- [SQL Basics in PostgreSQL](/raw/postgresql/wiki/concepts/sql-basics.md)
- [Transactions, MVCC, and Locking](/raw/postgresql/wiki/concepts/transactions-and-mvcc.md)
- [Window Functions and Aggregates](/raw/postgresql/wiki/concepts/window-and-aggregates.md)
- [psql — PostgreSQL Interactive Terminal](/raw/postgresql/wiki/entities/psql.md)
- [Activity Log](/raw/postgresql/wiki/log.md)
- [Operations and Reference Catalog](/raw/postgresql/wiki/summaries/operations-and-reference-catalog.md)
- [Data Modeling and Type Selection](/raw/postgresql/wiki/syntheses/data-modeling-and-types.md)
- [Query Performance Tuning](/raw/postgresql/wiki/syntheses/query-performance-tuning.md)